What is the test for determining whether a law enforcement officer violated the Fourth Amendment by approaching a person in the street and speaking to them?

"The first question that . . . must [be] answer[ed] is whether [the law enforcement officer's interaction] with Defendant was a seizure or, instead, was voluntary and consensual." United States v. Crapser, 472 F.3d 1141, 1145 (9th Cir. 2007). "When an encounter is voluntary, no constitutionally protected right is implicated." United States v. Summers, 268 F.3d 683, 686 (9th Cir. 2001).

"Law enforcement officers do not violate the Fourth Amendment's prohibition of unreasonable seizures merely by approaching individuals on the street or in other public places and putting questions to them if they are willing to listen." United States v. Drayton, 536 U.S. 194, 200 (2002).